lld 10.0 seems to generate this relocation for rdtsc_mb() ifunc in our libc.
Reported, reviewed, and tested by: dim (amd64, previous version)
Discussed with: emaste
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D23652
This allows for rtld to not issue two sigprocmask(2) syscalls for each
symbol binding operation in single-threaded processes. Rtld needs to
block signals as part of locking to ensure signal safety of the bind
process, because signal handlers might need to lazily resolve symbol
references.
As result, number of syscalls issued on startup by simple programs not
using libthr, is typically reduced 2x. For instance, for hello world,
I see:
non-sigfastblock
# (truss ./hello > /dev/null) |& wc -l
63
sigfastblock
# (truss ./hello > /dev/null) |& wc -l
37
Tested by: pho
Disscussed with: cem, emaste, jilles
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D12773
It's faster and more reliable to wait_for_pids than to sleep 1.
cem@ suggested just to remove auditd_stop() and use the rc.subr default
stop action (SIGTERM instead of audit -t), which has a built-in
wait_for_pids. That may be a better solution.
Discussed with: cem
Reviewed by: asomers
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D23223
They were introduced to take care of ifunc, but right now no architecture
provides ifunc'ed variants. Since rtld uses memset extensively this results in
a pessmization. Should someone want to use ifunc here they should provide a
mandatory symbol (e.g., rtld_memset).
See the review for profiling data.
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D23176
Move all MD statements into $MACHINE_ARCH/Makefile.inc.
Unconditionally apply version script to rtld, the interpreter is not
functional without it for long time.
Reviewed by: brooks, emaste
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D23083
The path is already absolute.
Noted and reviewed by: rstone
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D23121
instead of killing the process. The same behaviour of terminating
image activation if the $ORIGIN cannot be resolved for the main
object, is kept.
Reported by: Greg V <greg@unrelenting.technology>
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D23053
We know the binary relative name and can reliably calculate cwd path.
Because realpath(3) was already linked into ld-elf.so.1, reuse it
there to resolve dots and dotdots making the path more canonical.
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D23014
People use rc.conf inside vnet jails to configure networking setups.
Presumably because some sysctl were not virtualised up until r356527 the
script was not run for vnet jails leaving the rc.conf options without
effect for non-obvious reasons. Run the netoptions startup script also
for VNET jails now to make the rc.conf options work.
PR: 243193
MFC after: 2 weeks
binpath local was changed from char array to a char pointer, update
strlcpy/strlcat uses.
Reported by: Coverity through vangyzen
CID: 1412239 and 1412240
Reviewed by: emaste, imp, vangyzen
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D23090
When rtld is directly executed with arguments, it has to move the
program arguments, environment and elf aux data up a few slots to
remove its own arguments before the process being executed sees
them. When copying the environment, rtld was incorrectly testing
whether the location about to be written to currently contained
NULL, when was supposed to check whether it had just copied the
NULL terminator of the environment string. This had the result
that the ELF aux data was mostly treated as environment variables,
and rtld would quickly crash when it tried to access required
ELF aux data that it didn't think was present.
Differential Revision: https://reviews.freebsd.org/D23008
Reviewed by: kib
MFC after: 1 month
When activated in direct exec mode, kernel-provided AT_EXECPATH points
to the interpreter. We need to recalculate auxv to point to the
string with the path to the executable which is actually executed.
The somewhat problematic case is when the executable path is relative
and either $PATH use is not enabled or it contains '/' so $PATH search
is not performed. In this case resulting AT_EXECPATH is relative, I
might fix this later.
Reported and reviewed by: rstone
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D22894
Summary:
As a transition aide, implement an alternative elfN_freebsd_fixup which
is called for old powerpc binaries. Similarly, add a translation to rtld to
convert old values to new ones (as expected by a new rtld).
Translation of old<->new values is incomplete, but sufficient to allow an
installworld of a new userspace from an old one when a new kernel is running.
Test Plan:
Someone needs to see how a new kernel/rtld/libc works with an old
binary. If if works we can probalby ship this. If not we probalby need
some more compat bits.
Submitted by: brooks
Reviewed by: jhibbits
Differential Revision: https://reviews.freebsd.org/D20799
As PowerPC is moving to clang, we can finally start taking advantage of
IFUNC.
Implement the MD parts of IFUNC handling for rtld.
Currently, it is necessary to look for R_PPC_IRELATIVE in the PLT in
addition to RELA. This is an ABI violation, but LLD9 has some .iplt bugs
that require this as a workaround.
Reviewed by: jhibbits
Differential Revision: https://reviews.freebsd.org/D22855
As PowerPC is moving to clang, we can finally start taking advantage of
IFUNC.
Implement the MD parts of IFUNC handling for rtld.
Currently, it is necessary to look for R_PPC_IRELATIVE in the PLT in
addition to RELA. This is an ABI violation, but LLD9 has some .iplt bugs
that require this as a workaround.
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D22789
When a PT_LOAD segment has a zero p_filesz, skip the data mmap, as mmapping
zero bytes from a file is an error.
A PT_LOAD with zero p_filesz is legal (but somewhat uncommon due to segment
merging in modern linkers, as it is more efficient to merge .data and .bss
by just extending p_memsz in the previous segment, assuming compatible
page protection.)
This was seen on ports/graphics/glew on a powerpc64 ELFv2 experimental
build.
Submitted by: Alfredo Dal'Ava Junior <alfredo.junior@eldorado.org.br>
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D22634
Update a bunch of Makefile.depend files as
a result of adding Makefile.depend.options files
Reviewed by: bdrewery
MFC after: 1 week
Sponsored by: Juniper Networks
Differential Revision: https://reviews.freebsd.org/D22494
Leaf directories that have dependencies impacted
by options need a Makefile.depend.options file
to avoid churn in Makefile.depend
DIRDEPS for cases such as OPENSSL, TCP_WRAPPERS etc
can be set in local.dirdeps-options.mk
which can add to those set in Makefile.depend.options
See share/mk/dirdeps-options.mk
Reviewed by: bdrewery
MFC after: 1 week
Sponsored by: Juniper Networks
Differential Revision: https://reviews.freebsd.org/D22469
TP points to the start of the TLS block after the tcb, but
Obj_Entry.tlsoffset includes the tcb, so subtract the size of the tcb
to compute the offset relative to TP.
This is identical to the same fixes for powerpc in r339072 and r342671.
Reviewed by: James Clarke
Sponsored by: DARPA
Differential Revision: https://reviews.freebsd.org/D22661
o Remove All Rights Reserved from my notices
o imp@FreeBSD.org everywhere
o regularize punctiation, eliminate date ranges
o Make sure that it's clear that I don't claim All Rights reserved by listing
All Rights Reserved on same line as other copyright holders (but not
me). Other such holders are also listed last where it's clear.
Before this commit, the save-entropy script rotates entropy files
like logs. This involves creating a new file that holds the entropy
and renaming of all existing entropy files. However, the entropy
data do not really need to be kept in a particular order, and
replacing the oldest file is sufficient.
This commit replaces the rotation with a scan in the
[1..entropy_save_num] space that finds the first empty slot, or
the slot of the oldest file, and writes entropy into that slot.
This also fixes an issue that prevents save-entropy from saving
any entropy when there is one non-regular file in any slot as a
side effect.
Based on an earlier patch from peterj@.
PR: 134225
Reported by: peterj
Reviewed by: csprng (cem, markm)
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D22612
When a system has no internet connection, or when it is configured to obtain
ntpd leapfiles from some source other than the internet, or even when the
sysadmin has decided for some reason to customize ntp.conf to eliminate use
of the leapfile, the rc.d/ntpd script emits various error messages related
to the file.
This change allows setting the rc var ntp_db_leapfile to NONE to disable all
automatic processing related to that file in rc.d/ntpd.
Differential Revision: https://reviews.freebsd.org/D22461
Four bytes of padding are needed in the regular powerpc case to bring the
stack frame size up to a multiple of 16 bytes to meet ABI requirements.
Fixes odd hangs I was encountering during testing.
Summary:
We need to save off the full 64-bit register, not just the low 32 bits,
of all registers getting saved off in _rtld_bind_start. Additionally,
we need to save off the other SPE registers (SPEFSCR and accumulator),
so that their program state is not affected by the PLT resolver.
Reviewed by: bdragon
Differential Revision: https://reviews.freebsd.org/D22520
Each boot, regenerate /var/run/os-release based on the currently running
system. Create a /etc/os-release symlink pointing to this file (so that this
doesn't create a new reason /etc can not be mounted read-only).
This is compatible with what other systems do and is what the sysutil/os-release
port attempted to do, but in an incomplete way. Linux, Solaris and DragonFly all
implement this natively as well. The complete standard can be found at
https://www.freedesktop.org/software/systemd/man/os-release.html
Moving this to the base solves both the non-standard location problem with the
port, as well as the lack of update of this file on system update.
Bump __FreeBSD_version to 1300060
PR: 238953
Differential Revision: https://reviews.freebsd.org/D22271
FreeBSDlua ("flua") is a FreeBSD-private lua, flavored with whatever
extensions we need for base system operations. We currently support a subset
of lfs and lposix that are used in the rewrite of makesyscall.sh into lua,
added in r354786.
flua is intentionally written such that one can install standard lua and
some set of lua modules from ports and achieve the same effect.
linit_flua is a copy of linit.c from contrib/lua with lfs and lposix added
in. This is similar to what we do in stand/. linit.c has been renamed to
make it clear that this has flua-specific bits.
luaconf has been slightly obfuscated to make extensions more difficult. Part
of the problem is that flua is already hard enough to use as a bootstrap
tool because it's not in PATH- attempting to do extension loading would
require a special bootstrap version of flua with paths changed to protect
the innocent.
src.lua.mk has been added to make it easy for in-tree stuff to find flua,
whether it's bootstrap-flua or relying on PATH frobbing by Makefile.inc1.
Reviewed by: brooks, emaste (both earlier version), imp
Differential Revision: https://reviews.freebsd.org/D21893
to disable mounting Linux-specific filesystems under /compat/linux
when 'linux_enable' is set to YES.
Reviewed by: netchild, ian (earlier version)
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D22320
Alter bsd.compat.mk to set MACHINE and MACHINE_ARCH when included
directly so MD paths in Makefiles work. In the process centralize
setting them in LIBCOMPATWMAKEENV.
Alter .PATH and CFLAGS settings in work when the Makefile is included.
While here only support LIB32 on supported platforms rather than always
enabling it and requiring users of MK_LIB32 to filter based
TARGET/MACHINE_ARCH.
The net effect of this change is to make Makefile.libcompat only build
compatability libraries.
Changes relative to r354449:
Correct detection of the compiler type when bsd.compat.mk is used
outside Makefile.libcompat. Previously it always matched the clang
case.
Set LDFLAGS including the linker emulation for mips where -m32 seems to
be insufficent.
Reviewed by: imp, kib (origional version in r354449)
Obtained from: CheriBSD (conceptually)
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D22251
Alter bsd.compat.mk to set MACHINE and MACHINE_ARCH when included
directly so MD paths in Makefiles work. In the process centralize
setting them in LIBCOMPATWMAKEENV.
Alter .PATH and CFLAGS settings in work when the Makefile is included.
While here only support LIB32 on supported platforms rather than always
enabling it and requiring users of MK_LIB32 to filter based
TARGET/MACHINE_ARCH.
The net effect of this change is to make Makefile.libcompat only build
compatability libraries.
Reviewed by: imp, kib
Obtained from: CheriBSD (conceptually)
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D22251
Previously the watchdog timeout message was appended to the last entry
in the "Waiting for PIDS" list, resulting in a message like
Waiting for PIDS: 31299 31296 90201 9020090 second watchdog timeout
expired. Shutdown terminated.
Print a newline to separate the watchdog timeout message. Also perform
the kill before logging or echoing the message.
PR: 241072
MFC after: 1 month
Sponsored by: The FreeBSD Foundation
This change allows to specify a watchdog(9) timeout for a system
shutdown. The timeout is activated when the watchdogd daemon is
stopped. The idea is to a prevent any indefinite hang during late
stages of the shutdown. The feature is implemented in rc.d/watchdogd,
it builds upon watchdogd -x option.
Note that the shutdown timeout is not actiavted when the watchdogd
service is individually stopped by an operator. It is also not
activated for the 'shutdown' to the single-user mode. In those cases it
is assumed that the operator knows what they are doing and they have
means to recover the system should it hang.
Significant subchanges and implementation details:
- the argument to rc.shutdown, completely unused before, is assigned to
rc_shutdown variable that can be inspected by rc scripts
- init(8) passes "single" or "reboot" as the argument, this is not
changed
- the argument is not mandatory and if it is not set then rc_shutdown is
set to "unspecified"
- however, the default jail management scripts and jail configuration
examples have been updated to pass "jail" to rc.shutdown, just in case
- the new timeout can be set via watchdogd_shutdown_timeout rc option
- for consistency, the regular timeout can now be set via
watchdogd_timeout rc option
- watchdogd_shutdown_timeout and watchdogd_timeout override timeout
specifications in watchdogd_flags
- existing configurations, where the new rc options are not set, should
keep working as before
I am not particularly wed to any of the implementation specifics.
I am open to changing or removing any of them as long as the provided
functionality is the same (or very close) to the proposed one.
For example, I think it can be implemented without using watchdogd -x,
by means of watchdog(1) alone. In that case there would be a small
window between stopping watchdogd and running watchdog, but I think that
that is acceptable.
Reviewed by: bcr (man page changes)
MFC after: 5 weeks
Relnotes: yes
Differential Revision: https://reviews.freebsd.org/D21221
'sysvipc' - it has nothing to do with ABIs, and I'd like to later
rename 'abi' to 'linux', which better describes its purpose and also
matches the rcvar name.
Reviewed by: emaste
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D21615
has become very trigger-happy with libc++ 9.0.0.
It does not help that gcc's implementation of this warning is even more
trigger-happy, in the sense that it already warns on the declaration
itself, not when you are using it. This is very annoying with our use
of -Wsystem-headers. That should really be disabled for gcc.
After the aux vector is moved, it is necessary to re-digest aux_info so the
pointers are updated to the new locations.
This was causing thread creation to fail on powerpc64 when using direct
execution due to a nonsense value being read for aux_info[AT_STACKPROT].
Approved by: jhibbits (mentor)
Differential Revision: https://reviews.freebsd.org/D21656
std::auto_ptr in a whole bunch of individual Makefiles, make the warning
globally non-fatal instead. This is similar to what was done to many
more non-fatal warnings from newer gcc versions.
A user may set ${name}_env variable in rc.conf(5) in order to set additional
environment variables for a service command. Unfortunately, at the moment
this variable is only honored when the command is specified via the command
variable. Those additional environment variables coming from ${name}_env
are never set if the service is started via the ${rc_arg}_cmd variable (for
example start_cmd).
PR: 239692
Reviewed by: bcr, jilles
Approved by: src (jilles)
Differential Revision: https://reviews.freebsd.org/D21228
It doesn't need to be in runtime and might help people who want to
experiment with other rc system or don't use one (like in small
embedded mfsroot).
Reviewed by: bapt, gjb
Differential Revision: https://reviews.freebsd.org/D21499
In the past, this allocator seems to have allocated things larger than
a page seperately. Much of this code was removed at some point (perhaps
along with sbrk() used) so remove the rest. Instead, keep allocating in
power-of-two bins up to FIRST_BUCKET_SIZE << (NBUCKETS - 1). If we want
something more efficent, we should use a fancier allocator.
While here, remove some vestages of sbrk() use. Most importantly, don't
try to page align the pagepool since it's always page aligned by mmap().
Reviewed by: kib
Obtained from: CheriBSD
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D21453
In Seventh Edition UNIX, the last pointer passed to free() was
guaranteed to not actually have been freed allowing memory to be
"compacted" via the following pattern:
free(foo);
foo = realloc(foo, newsize);
Further, Andrew Koenig reports in "C Traps and Pitfalls" that the
original realloc() implementation required this pattern.
The C standard is clear that this is Undefined Behavior. Modern
allocators don't support it and no portable code could rely on it so
remove this support.
Note: the removed implementation contains an off-by-one error and if
an item isn't found on the freelist, then twice as much memory as the
largest possible allocation will be copied.
Reviewed by: kib, imp
Obtained from: CheriBSD
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D21296
Instead of restoring the saved values of argc, argv and envp,
these must be loaded from the stack that _rtld() modifies.
This fixes rtld direct exec mode.
E.g.: /libexec/ld-elf.so.1 /bin/ls
Reviewed by: jhibbits
Differential Revision: https://reviews.freebsd.org/D21131
First, amd64 version of the script cannot work at least due to the
wrong architecture specification. Second, kernel can activate shared
objects for long time, due to PIE support.
It seems the intent was to allow ld-elf.so.1 to be build and used as
an executable. Since we have direct exec mode implemented for dso
ld-elf.so.1, the non-functional and commented out scripts can be
finally removed.
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Update login(1), its manual pages, similar utilities, and motd.5 to refer to
the new location.
Suggested by: delphij@ (re: r349256)
Reviewed by: bcr (manpages), delphij
Differential Revision: https://reviews.freebsd.org/D20721
Move the bluetooth related files from FreeBSD-runtime to a new package named
FreeBSD-bluetooth
The FreeBSD runtime is only intended to have everything for a working
FreeBSD installation and bluetooth isn't needed for that.
Reviewed by: bapt, gjb
Differential Revision: https://reviews.freebsd.org/D20959
In 2013 the security chapter of the Handbook was updated in r42501 to
suggest limiting access to the system accounting file [*1] by creating the
initial file with a mode of 0600. This was in part based on a discussion in
the forums [*2]. Unfortunately, this advice is overridden by the fact that a
new file is created as part of periodic daily processing, and the file mode
is set by the rc.d/accounting script.
These changes update the accounting script to create the directory with mode
0750 if it doesn't already exist, and to create the daily file with mode
0640. This limits write access to root only, read access to root and members
of wheel, and eliminates world access completely. For admins who want to
prevent even members of wheel from accessing the files, the mode of the
/var/account directory can be manually changed to 0700, because the script
never creates or changes that directory if it already exists.
The accounting_rotate_log() function now also handles the error cases of no
existing log file to rotate, and attempting to rotate the file multiple
times (.0 file already exists).
Another small change here eliminates the complexity of the mktemp/chmod/mv
sequence for creating a new acct file by using install(1) with the flags
needed to directly create the file with the desired ownership and
modes. That allows coalescing two separate if checkyesno accounting_enable
blocks into one.
These changes were inspired by my investigation of PR 202203.
[1] https://www.freebsd.org/doc/handbook/security-accounting.html
[2] http://forums.freebsd.org/showthread.php?t=41059
PR: 202203
Differential Revision: https://reviews.freebsd.org/D20876
I found this on one of the CheriBSD Jenkins builders. Using
beforelinking instead of ${PROG} should fix the dependency for the
DEBUG_FILES case.
Reviewed by: brooks
Currently RTLD is linked against libc_nossp_pic which means that any libc
symbol used in rtld can pull in a lot of depedencies. This was causing
symbol such as __libc_interposing and all the pthread stubs to be included
in RTLD even though they are not required. It turns out most of these
dependencies can easily be avoided by providing overrides inside of rtld.
This change is motivated by CHERI, where we have an experimental ABI that
requires additional relocation processing to allow the use of function
pointers inside of rtld. Instead of adding this self-relocation code to
RTLD I attempted to remove most function pointers from RTLD and discovered
that most of them came from the libc dependencies instead of being actually
used inside rtld.
A nice side-effect of this change is that rtld is now 22% smaller on amd64.
text data bss dec hex filename
0x21eb6 0xce0 0xe60 145910 239f6 /home/alr48/ld-elf-x86.before.so.1
0x1a6ed 0x728 0xdd8 113645 1bbed /home/alr48/ld-elf-x86.after.so.1
The number of R_X86_64_RELATIVE relocations that need to be processed on
startup has also gone down from 368 to 187 (almost 50% less).
Reviewed By: kib
Differential Revision: https://reviews.freebsd.org/D20663
Summary:
PowerPC has two PLT models: BSS-PLT and Secure-PLT. BSS-PLT uses runtime
code generation to generate the PLT stubs. Secure-PLT was introduced with
GCC 4.1 and Binutils 2.17 (base has GCC 4.2.1 and Binutils 2.17), and is a
more secure PLT format, using a read-only linkage table, with the dynamic
linker populating a non-executable index table.
This is the libc, rtld, and kernel support only. The toolchain and build
parts will be updated separately.
Reviewed By: nwhitehorn, bdragon, pfg
Differential Revision: https://reviews.freebsd.org/D20598
MFC after: 1 month
Use appropriate fsyncs to persist the rewritten /etc/motd file, when a
rewrite is performed.
Reported by: Jonathan Walton <jonathan AT isilon.com>
Reviewed by: allanjude, vangyzen
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D20701
The logic I originally wrote to detect whether a driftfile option was in the
set of flags was based on the result of removing the pattern *flag* being an
empty string. That didn't handle the case where the string was empty to
begin with. Doh! So now it also specifically checks for an empty string.
The result of the bad check was that ntpd would run without a driftfile, but
it would do so only if it was running as root instead of the non-priveleged
ntpd user, which isn't a typical case. Ntpd runs fine without a driftfile,
although it does take it longer to stabilize the clock frequency at startup.
Reported by: avg@
Pointy hat: ian@
MFC after: some testing
Tag saved entropy files as "nodump," to signal that the files should not be
backed up by dump(8) or other automated backup software that honors the file
flag.
Do not produce an error if the target file resides on a filesystem that does
not support file flags (e.g., msdos /boot).
Reviewed by: delphij
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D20358
- Remove an extra space after "usage:".
- Avoid lines exceeding 80 columns.
Based on notes from rgrimes.
MFC with: r348066
Event: Waterloo Hackathon 2019
There were several (apparently) copy-pasted NEED validation macros,
leading to the same error string for different issues. Change the
YP and NTP tags so they are distinct.
PR: 30863
Submitted by: Dan Lukes <dan@obluda.cz>
Reviewed by: markj
MFC after: 1 week
Event: Waterloo Hackathon 2019
ed(4) and ep(4) have been removed. fxp(4) remains popular in older
systems, but isn't as future proof as em(4).
Reviewed by: bz, jhb
MFC after: 3 days
Differential Revision: https://reviews.freebsd.org/D20311
Use roundup2() and rounddown2() instead of inlining them.
Get rid of the fd local variable, use literal -1 for the mmap argument.
Use MAP_FAILED as mmap(2) failure indicator.
After that, apply some style.
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
kern_execve() locks text vnode exclusive to be able to set and clear
VV_TEXT flag. VV_TEXT is mutually exclusive with the v_writecount > 0
condition.
The change removes VV_TEXT, replacing it with the condition
v_writecount <= -1, and puts v_writecount under the vnode interlock.
Each text reference decrements v_writecount. To clear the text
reference when the segment is unmapped, it is recorded in the
vm_map_entry backed by the text file as MAP_ENTRY_VN_TEXT flag, and
v_writecount is incremented on the map entry removal
The operations like VOP_ADD_WRITECOUNT() and VOP_SET_TEXT() check that
v_writecount does not contradict the desired change. vn_writecheck()
is now racy and its use was eliminated everywhere except access.
Atomic check for writeability and increment of v_writecount is
performed by the VOP. vn_truncate() now increments v_writecount
around VOP_SETATTR() call, lack of which is arguably a bug on its own.
nullfs bypasses v_writecount to the lower vnode always, so nullfs
vnode has its own v_writecount correct, and lower vnode gets all
references, since object->handle is always lower vnode.
On the text vnode' vm object dealloc, the v_writecount value is reset
to zero, and deadfs vop_unset_text short-circuit the operation.
Reclamation of lowervp always reclaims all nullfs vnodes referencing
lowervp first, so no stray references are left.
Reviewed by: markj, trasz
Tested by: mjg, pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 month
Differential revision: https://reviews.freebsd.org/D19923
- Remove dead and most likely rotten MALLOC_DEBUG, MSTAT, and RCHECK options.
- Remove unused headers.
- Remove one case of undefined behavior where left shift could overflow.
It is impossible on practice for rtld and libthr consumer.
PR: 237577
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
